To remove a skin biopsy specimen or to remove a mole or other skin lesion it is known to incise the skin along a closed line completely penetrating the skin and to then remove the specimen or unwanted skin and tissue containing the lesion by further sharp and blunt dissection, and to thereafter perform a skin closure procedure. It is also known in the incision step to use punch-type instruments having sharp blades which accurately cut closed lines in the skin and which can be held and manipulated by one hand of the surgeon while his or her other hand is used to stretch the skin at the site of the incision. Exemplary ones of such instruments are disclosed in U.S. Pat. Nos. 1,577,979; 3,990,541; 5,123,907; and 5,183,053.
In making a skin incision of the type in question it is usually desirable to have it be of generally elliptical shape. Such an elliptical incision is important for achieving a more suitably appearing skin closure, and is especially beneficial if used while the skin is stretched and held in a cross-grain direction with respect to the skin lines of Langer while the incision is made. U.S. Pat. No. 5,183,053 shows a punch-type surgical instrument for cutting along a generally elliptical closed line, and U.S. Pat. No. 5,123,907 discusses the stretching of the skin relative to the skin's lines of Langer during the incision step.
If an attempt is made to make an elliptical incision free hand using a scalpel and by cutting at different times along two curved incisional lines defining the opposite sides of an ellipse, it is often difficult to make the two incisional lines perfectly symmetrical and therefore the subsequent skin closure, due to several factors, may be irregular. It is also difficult to properly evenly stretch the skin with respect to the lines of Langer while the incision is performed free hand. Therefore, the use of a punch-type instrument to avoid these problems is recommendable.
The amount of skin and adjacent tissue to be removed in the involved surgical procedure will vary from situation to situation, and therefore it is desirable that the punch-type instruments, if used, be available in different sizes so that in each procedure the surgeon will be able to make an incision of a size favorably suiting the biopsy specimen to be taken or lesion to be removed. Further, because of the nature of its use the instrument should be one which is of relatively inexpensive construction so that it can be used once and then be disposed of.
The general object of the invention is therefore to provide a punch-type instrument for skin incision which may be made with a blade having a generally elliptical shape, in which the blade is stably held relative to the handle to allow the blade to be moved by the handle in various directions without any looseness or slippage between the blade and handle, which can be easily made to cut incisions of different size, and which can be made of a sufficiently low cost as to render it suitably disposable after a single use.